Device for treating cardiac arrest

ABSTRACT

The invention relates to a device for treating an individual suffering from cardiac or circulatory arrest or from a stroke, comprising a blood withdrawal device (BE) that is applied to the individual (P), an analysis unit (BA) which is directly or indirectly connected to the blood withdrawal device for detecting a blood analysis result (BAE) providing at least one characteristic of the blood, directly or indirectly connected to a blood return device (BR) that is applied to the individual (P) and is designed to deliver a substance to the individual via the return device (BR).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a device for treating an individual sufferingfrom cardiac insufficiency, cardiac arrest, circulatory arrest orstroke.

2. Description of the Prior Art

Given the current level of knowledge and the current therapeuticmethods, individuals, more particularly patients, who have sufferedcardiac arrest, can only be resuscitated without damage to the brain orthe heart functions if cardiopulmonary resuscitation is successfullycarried out within a period of three to five minutes after the cardiacarrest has occurred. Resuscitation carried out with a further time delayinevitably leads to severe cerebral damage due to reperfusion withnormal blood which causes massive damage to the ischaemic tissue.

Ischaemic and reperfusion modifications in tissues mainly play a centralrole in heart surgery. For example mycocardial ischaemia is eitherinduced by the surgeon himself, for instance as part of global ischaemiathrough aortic clamping, or also during a heart transplant and/orregionally in “off-pump surgery” for application of a coronary by-pass.However, emergency operations are also performed on patients withmyocardial ischaemia who, for example, are suffering from cardiogenicshock, acute coronary occlusion or a condition immediately afterresuscitation. For these reasons heart surgeons have been intensivelyoccupied with ischaemia and reperfusion phenomena for decades.

In accordance with current knowledge, it can be assumed that ischaemia,even long-lasting ischaemia, only causes relatively small structuraldamage to the heart muscle. However, if after such an ischaemic attackthe myocardium is reperfused with normal blood under “physiological”conditions, an additional damaging mechanism occurs explosively, whichin the meantime has been well researched as “reperfusion damage”. Onreperfusion of an ischaemically damaged myocardium with normal blood,processes suddenly occur which can definitively destroy the alreadydamaged tissue.

To prevent or completely hinder the reperfusion damage occurring throughreperfusion with normal blood, concepts have been developed which afterrevascularization initially endeavour to treat the ischaemically damagedmyocardium, whereby both the composition of the initial reperfusate andthe conditions of the initial perfusion are aimed at treating the damageoccurring during the ischaemia and/or ruling out possibly occurringreperfusion damage right from the start.

The concept of controlled reperfusion is based on the one hand onmodifying the initial reperfusate differently from the body's own bloodas well as modifying the conditions of the initial reperfusion.

In connection with this, DE 696 31 046 T2 discloses a device fortreating a patient with cardiac arrest which uses the known method ofselective aortic arch perfusion, SAAP in short, in which in order tocarry out relatively isolated perfusion of the heart and brain, aballoon occlusion catheter is applied, usually via the patient's femoralartery, to the location of the descending aortic arch and then dilated,after which an oxygenated blood substitute solution, for exampleperfluorocarbon emulsion or a polymerized haemoglobin solution is theninfused via the lumen of the SAAP catheter. The blood substitutesolution, also known as a protective solution, is administeredintracorporeally using a pulsing device with a pulsating rhythm. In avariant embodiment the known device has a blood withdrawal means, withwhich blood can be withdrawn from the patient which is taken to bloodoxygenation means for oxygenation and, together with a protectivesolution added to the oxygenated blood, is infused into the patient viablood return means. It should be noted here that to carry out selectiveaortic arch perfusion and thus to use the above device, a surgicalprocedure and the associated clinical infrastructure are necessary.

U.S. Pat. No. 5,195,942 discloses a comparable procedure forresuscitating a person, in which by inflating a balloon catheter in theregion of the ascending aorta in order to increase the blood flow intothe coronary arteries, a blood-compatible, oxygen liquid is injected forflowing on into the coronary arteries.

U.S. Pat. No. 7,387,798 B2 describes a method for the resuscitation ofpatients suffering from cardiac arrest, in which a liquor fluid is takenfrom the subarachnoid area of the patient's central nervous system. Anartificially composed cerebrospinal fluid containing a large number ofcomponents, such as sodium, potassium, calcium, magnesium, water,polypeptides, insulin and ATP, is then infused, whereupon conventionalcardiopulmonary resuscitation is carried out

For resuscitating a patient or an animal, U.S. Pat. No. 5,416,078discloses administering a solution of Deferoxamine with water-solublebiopolymers to the patient to be treated.

WO 94/21195 describes administering an A3 adenosine receptor agonist forpreparing the organ in order to protect it against ischaemic damage.

In EP 1 021 084 B1 a method of eliminating or reducing ischaemic damageto an organ is set out. Here, the damaged organ is rinsed with abuffered physiological solution in order to remove acidic products whichhave accumulated in the organ during the period of oxygen deficiency.

U.S. Published Application 2005/0101907 A1 describes an automatic systemfor the resuscitation of a patient in which a single fluid is infused inrelation to the fluid inflow as function of physiological parameters ofthe patient.

A comparable automatic infusion system for treating trauma patients isdisclosed in U.S. Pat. No. 5,938,636, for infusion of an administeredfluid into the patient with the infusion pressure and infusion flowbeing sensor-recorded and computer-monitored.

DE 10 2008 024 471 A1 describes a heart-lung by-pass device which can beconnected to a patient by one tube to the arterial and one tube to thevenous blood vessel system. Extracorporeally, between the tubes, thereis a blood flow line along which bi-directionally operating pumps and afluid reservoir can be provided. Controllable fluid control valvesfitted with sensors are also arranged along the blood flow line. Throughbi-directional pump operation, the lungs assume the function of theoxygenators of the heart-lung by-pass device.

U.S. Pat. No. 5,308,320 describes a portable resuscitation device forcardiac arrest patients having blood withdrawal means, a pump for movingthe blood within the devices, means for oxygenating the blood and meansfor returning the oxygen-enriched blood back into the blood circulation.

SUMMARY OF THE INVENTION

The invention is a device for providing full resuscitation of a patientwithout the risk of ischaemic damage during a period of time between theonset of the cardiac arrest and the initiation of resuscitation measureswhich is considerably greater than the previous critical time window of3 to 5 minutes. The device allows as fully automatic resuscitation aspossible so that no complicated therapeutic precautions have to be takenin situ. The device also is lightweight and portable and independentlyoperable as possible so that it can be used as an instrument foremergency medicine on site. The device is useful for a cardiac arrest,and for cardiac insufficiency or a stroke, based on the same principles.

The invention exerts, by way of at least one sensor-supported bloodanalysis of the individual's blood, an individual bloodanalysis-dependent influence on the blood taken from the individual sothat an individually selected substance or an individually producedsubstance mixture is added or mixed to the blood taken from theindividual to obtain “modified blood.” The thus obtained “modifiedblood” is reperfused into the individual as a reperfusate with the goalof partially or fully preventing the ischaemic tissue damage otherwiseoccurring on activation of the natural or artificially-supported bloodcirculation system or on initial blood supply to areas of tissuedisconnected from the natural blood circulation for a shorter or longerperiod.

The device in accordance with the invention for treating an individualwith cardiac arrest or stroke, includes a blood withdrawal deviceattachable to the individual for withdrawing at least part of the bloodfrom an individual, an analysis unit directly or indirectly connected tothe blood withdrawal means for recording and providing at least oneproperty of the blood in the form of blood analysis result, an operativeunit, which is indirectly or directly connected to a blood return deviceattachable to the individual and designed to administer a substance tothe individual via the return means. The operative unit has at least onereservoir in which at least two substances are stored. The reservoirunit is combined with a dosage unit, which, taking into consideration ablood analysis result determined by the analysis unit, selects at leastone of the two substances or prepares a mixtures of at least two of thesubstance. The at least one selected substance or the mixture can thenbe applied to the individual directly or indirectly via the blood returndevice.

The individual is, more particularly, a human or animal patient. Theterms “patient” and “individual” are used synonymously here. Cardiacinsufficiency is understood, for example, as a traumatic or pathologicalreduction in the output of the heart, which may be caused by a heartattack, cardiogenic shock or heart failure.

In one variant, the device of the invention also has a sensor device,recording at least one property of the individual's blood, whichgenerates a sensor signal, which is then evaluated by the analysis unitand made available as a blood analysis. The analysis unit isfundamentally suitable for working with the sensor unit so that a sensorsignal determined/generated by the sensor unit can be transmitted fromthe sensor unit to the analysis unit. The device can be produced withalready known sensors.

The sensor unit can comprise a plurality of sensors, of which eachsensor records at least one parameter or property of the blood.

In one variant, the sensor unit is designed as a non-invasive componentwhich can be directly or indirectly attached to the individual.

The blood withdrawal device for taking the blood are envisaged and setup to withdraw at least part of the blood from an individual before theblood is influenced by the operative unit. For this the blood withdrawaldevice is, for example, invasively attachable to the individual. In thisway at least two liters, more particularly at least three liters, moreparticularly at least four liters, or more particularly all the blood inthe individual's blood vessels, can be withdrawn.

Through the blood return device, the withdrawn and treated or influencedblood, that is the “modified blood,” can be returned into the body ofthe individual. The return means can also be invasively attached to theindividual.

On the one hand, at least one substance in the form of an additive tothe blood in the patient, for example, can be administered by way of aninjection into the infusion, or the patient's blood is removed from thepatient by way of blood withdrawal device and extracorporeally enrichedor treated with the at least one substance which is then reperfused intothe patient in the form of “modified blood.” It is also conceivable toremove essentially all the blood from a patient and, instead of thisblood, to return the “modified blood” or a solution, individuallyadapted to the patient and containing at least one substance, directlyto the patient in order to then be able to initiate the process ofresuscitation without tissue damage.

In one embodiment, the sensor unit is directly or directly connected tothe blood withdrawal device.

For the purpose of modification and/or manipulation of the patient's ownblood individually adapted to the patient situation, in one variant theoperative unit is controlled or regulated by an evaluation and controlunit on the basis of the analysis result which represents the patient'scurrent condition.

Advantageously, the analysis unit, the operative unit, the evaluationand the control unit are a portable and standard unit, in which thesensor unit is preferably part of the standard unit.

The sensor unit generates the sensor signal which represents the atleast one property of the blood taken from the patient and can betransmitted by cable or wirelessly to the analysis unit, whereby on thebasis of the analysis results, the evaluation and control unit generatescontrol or regulating signals. These can be used, for example, to selector dose the type and/or quantity the substance or substance mixture tobe added. Here, the sensor unit records at least one of the followingparameters: pH value, partial oxygen pressure (pO₂), partial carbondioxide pressure (pCO₂), potassium content (K), sodium content (Na),calcium content (Ca), base excess (BE), lactate value (La) and glucosecontent (Gu).

The device in accordance with the invention is preferably also portableand easy to operate, more particularly as a fully autonomous unit, sothat it is not necessarily exclusively usable by medical specialistpersonnel. One form of embodiment comprises a portable handy unit, fromwhich only two tubes extend, which on the patient side are connected tothe blood vessel system. One tube is for taking the blood from thepatient, via which the patient's blood automatically flows out into theunit, in which an analysis of the blood and corresponding modificationof the blood take place. The appropriately “modified blood” is thenreperfused into the patient via the other tube. Alternatively, thisdevice also makes it possible, before the “modified blood” is returnedto the patient, to administer to the patient an individually composedperfusion solution, the composition of which depends on the result ofthe analysis of the patient's own blood. For a successful treatmentoutcome, it is therefore conceivable in a first step to largelysubstitute the blood with an individually composed perfusion solution.Only later on during the treatment is the aforementioned “modifiedblood” administered, possibly after successfully carrying out furtherresuscitation measures.

In one variant, the operative unit dispenses the at least one substanceto the individual or the blood in dosed form at the correct temperatureand/or pressure.

Preferably, a monitoring unit is provided which has at least onemeasuring device for recording the at least one parameter of theindividual, which is selected from the group of physiological parametersof the individual, comprising mean arterial pressure, central nervouspressure, pulmonary arterial pressure, oxygen saturation and bloodtemperature, whereby the monitoring unit is connected to an evaluationand monitoring device for at least unilateral data exchange.

Fundamentally, the blood is taken from the patient as a bodily fluid.However, the embodiments of the device relating to blood as the bodilyfluid can also be used for other bodily fluids in an analogous manner.

The blood withdrawal device to be applied to the patient is preferablyconnected via a blood flow path, in the simplest case in the form of ahollow tube, to the blood return device applicable to the patient,whereby, more particularly, along the blood flow path the reservoir unitof the operative unit is provided, which contains at least twosubstances, and from which at least one of the substances to be selectedor a substance mixture can be added to the blood flow path or the bloodreturn device.

Along the blood flow path a heat exchanger unit can also be providedwhich is directly or indirectly connected to the return means. At leastone conveying device integrated along the blood flow path is also foradjusting the blood flow along the blood flow path in order to assuresimple transporting of the blood from the individual's body and of themodified blood into the individual's body. Preferably, for returning theblood to the body a further, separate conveying device is provided, withwhich flow characteristics can be set which are individual and above allindependent in terms of pulsability, flow pressure and speed.

For controlling all present conveying devices as well as the heatexchanger unit, the evaluation and control unit generates furthersignals, so that ultimately the flow pressure, the flow rate and/ortemperature of the at least one substance or the “modified blood” to bereturned to the patient can be set in a predetermined manner.

The analysis unit with its sensor unit is also arranged along the bloodflow path, so that in terms of individual blood parameters, moreparticularly a large number of blood parameters, the blood can beanalyzed and a blood analysis result is made available for furtherevaluation. The analysis preferably takes place online, that is on site,while the blood is being taken from the patient by the blood withdrawaldevice.

Taking into consideration the blood analysis result determined by theanalysis unit, the dosage unit connected to the reservoir unit brings apredeterminable quantity of the at least one substance from thereservoir unit and adds it into the blood flow path or to the bloodreturn device. As a result, with the aid of the dosage unit, anindividually composed reperfusate based on the current condition of thepatient to be treated is produced, which is then reperfused into thepatient via the applied blood return unit.

Particularly in the reperfusion of “modified blood” into the patient,but also in the simple administration of a perfusion fluid, the additionof at least one, more particularly many substances to the patient's ownblood or the perfusion solution as well as the perfusion itself, takesplace, with regard to the selection of the reperfusion pressure, theflow rate, the reperfusion duration and the temperature of thereperfusate, taking in consideration and adapted to the patient'scurrent sensor-recorded blood picture. The aforementioned monitor unitcan be used for this for example. In this way the selection and settingof the physiological reperfusion conditions can also take place takinginto consideration the physiological parameters determined by themonitoring unit.

The aforementioned evaluation and control unit, which can, for example,be connected both to the analysis unit and to the dosage unit for thepurpose of at least unilateral data exchange, is used to evaluate bloodanalysis results determined by the analysis unit and to determine thetype and quantity of the substances to be added to the patient's ownblood or the perfusion solution. The blood analysis result is evaluatedin the evaluation and control unit under predetermined evaluationcriteria, which can also take the physiological patient parametersrecorded by the monitoring unit into consideration.

Data transmission connections in the form of conventional datatransmission cables or wireless technologies are used for the at leastunilateral exchange of data.

As a result of the evaluation of the blood analysis result, theevaluation and control unit generates control signals which aretransmitted to the dosage unit for selecting the type and quantity ofthe substances to be added to the blood flow. In connection with this,the term “dosage unit” is understood as a technical device with which itis possible, from a number of substances stored in separate reservoirchambers, on the basis of defined mixing plan in which the selection ofthe relevant substances and the quantity of the substance to be added isdefined, to make a mixture which is ultimately to be added to thepatient's own blood. It is not necessary to premix the selectedsubstances before adding them to the patient's own blood as theseparate, dosable addition of individually selected substances to theblood flow path is also conceivable.

Preferably. the dosage unit has at least one mixing container, which hasindividually controllable dosing unit which are connected to theindividual reservoir chambers. In the mixing container, a substancemixture to be added to the bodily fluid of the individual is produced inthe mixing container in the form of a solution, a suspension or anemulsion. Thus, the substances stored in the reservoir chambers are notnecessarily fluid and an individual substance can also be present insolid or powder form or also in the gaseous phase. For example, thefollowing substances or substance classes from which an individualselection can be made to produce a substance mixture to be added to thebodily fluid of the individual can be stored in the individual reservoirchambers: alkaline or acidic buffer solution, substances affecting thesodium, potassium and/or calcium content, blood-thinning substances,free radical trapping agents, glutamate, aspartame,heart-rhythm-stabilizing substances (Lidocaine), substances influencingthe leukocyte count, osmotically-active substances, namely salts,glucoses, proteins.

In one variant, a filter unit for blood filtering is provided along ablood flow path between the blood withdrawal device and the blood returndevice. This filter may include a leukocyte filter for example.

In one variant along the blood flow path between the blood withdrawaldevice and the blood return device, directly upstream of the bloodreturn device a by-pass line is provided, through which some of the“modified blood” to be returned to the individual can be supplied to theanalysis unit and in the event of an anomalous nominal/actualcomparison, the dosage unit changes the quantity of the at least onesubstance supplied into the blood path flow for at least onedeterminable blood parameter.

In one variant, the individual components of the device are so compactand light in weight that the device is portable.

In one variant, along a blood flow path between the blood withdrawaldevice and the return device, an oxygenation and oxygen-depletion unitfor the blood is provided in order to match the oxygen content of themodified blood to be returned to the relevant requirements.

One form of embodiment of the device in accordance with the inventionincludes a portable base module, hereinafter referred to as CIRD (asacronym for Controlled Integrated Resuscitation Device. The CIRD basemodule has an extracorporeal blood flow path which can be applied by wayof suitable blood device and (blood) return device to the patient'sblood circulation, more particularly in the area of the femoral arteryand femoral vein. Along the extracorporeal blood flow path, the CIRDbase module has a conveying device for maintaining the blood flow, anoxygenator for enriching the blood with oxygen, as well as a device forCO₂ depletion and finally, a leukocyte filter, and can be modularlyexpanded with the aforementioned blood analysis unit as well as thepreviously described reservoir and dosing unit.

With the aid of such a device, for the automatic operation and controlof which the also previously mentioned evaluation and control unit isprovided, mostly in the form of a computer unit, it is possible toquickly and automatically analyze the blood taken from a patientsuffering from cardiac arrest and to determine exactly which compositionof additional substances has to be added to the patient's own blood.From the result of the blood analysis, and, possibly, also taking intoaccount the sensor-recorded physiological parameters of the patient, areperfusate is finally automatically produced which is individuallyadapted to the patient and introduced into the patient under optimizedconditions in terms of pulsability, flow pressure, flow rate and/ortemperature. This creates ideal conditions for the initial perfusion interms of the reperfusion pressure, the reperfusion flow and thereperfusion duration.

As the device in accordance with the invention allows continuousmonitoring of the patient's own blood, the reperfusion conditions andthe composition of the reperfusate can be adapted in situ or online,that is continuously, to the current condition of the patient beingreperfused. More particularly, through the in situ/online measurement ofcertain blood parameters, such as the concentration of potassium ions,lactate, glucose or the pH value etc. as well as through the combinedmeasurement of haemodynamic parameters by way of suitable monitoringsensors which record the flow resistance, temperature, the flow rate aswell as the flow pressure etc. within the blood flow path, automaticadjustments can be made as part of the controlled whole-bodyreperfusion.

The device in accordance with the invention for extracorporealwhole-body reperfusion was successfully tested in experiments on pigs.Fifteen minutes after controlled induced cardiac arrest in normothermicconditions, animals could be successfully resuscitated withoutnoticeable or measurable organ damage or neurological damage. Theseexperiments show, for the first time. that it is possible to achievefully functional neurological recovery, even 15 minutes after the onsetof cardiac arrest, a fact which is in sharp contrast to the model andlimitations of current conventional treatments. More particularly,through the lightweight and portable design of the device in accordancewith the invention, completely new perspectives are opened up foremergency medicine which could result in very many patients, who todayhave no chance of resuscitation and/or full recovery, not only beingable to be saved in future, but also to recover without neurologicaldamage.

The subject matter of the invention is also a method of treating anindividual suffering from cardiac arrest or stroke in which blood istaken from the individual which then undergoes a blood analysis, wherebytaking into consideration a blood analysis result determined by theanalysis unit and at least one evaluation criterion, from at least twostored substances the type and quantity of at least one of thesubstances or a substance mixture are determined, which in dosed form isadded to the removed blood to obtain “modified blood” which isreperfused into the individual or which is reperfused into theindividual in the form of perfusion solution in place of the removedblood.

In one variant of the method of the invention, the blood is taken fromthe individual before recording the properties and returned after addingthe at least one selected substance to the blood.

In one variant, the recording, evaluation and influencing take place ina closed control cycle.

In one variant of the method of the invention, the analysis result iscompared with a nominal value, and in the event of a quantitativelypredeterminable deviation from the nominal value, a substanceinfluencing the blood property forming the basis of the analysis resultis selected and introduced into the individual or the blood in aquantity depending on the quantitative deviation.

In one variant of the method of the invention, at least two liters, moreparticularly at least three liters, more particularly at least fourliters, and more particularly all the blood in the individual's bloodvessels, is to be withdrawn before reperfusion of the modified bloodtakes place.

In one variant of the method of the invention, the blood is taken fromthe patient over a period of 10 seconds to 3 minutes, more particularly20 seconds to 2 minutes, more particularly 30 seconds to 1 minute.

In one variant of the method of the invention, some of the “modifiedblood” is branched off for the purpose of repeated blood analysis, andif the at least one determined blood parameter deviates from the nominalvalue, a correction to the type and/or quantity of the at least oneadded substance takes place.

In one variant of the method of the invention, the procedures of takingthe blood, blood analysis, adding the at least one substance to theblood or perfusion solution as well as the reperfusion of the modifiedblood or perfusion solution take place in situ.

In one variant of the method, in addition to the blood analysis, atleast one physiological parameter of the individual is determined.Taking into consideration both the blood analysis result and also the atleast one physiological parameter of the individual, the type andquantity of the at least one substance to be added to the removed bloodor perfusion solution, as well as the pressure, flow rate andtemperature of a modified blood flow or solution to be reperfused intothe individual, are selected.

In one variant of the method of the invention, the reperfusion of the“modified blood” or perfusion solution into the individual takes placeat least two different parts of the body each with different reperfusionparameters in terms of pressure, flow rate, temperature and/orreperfusion duration.

In one variant of the method of the invention, the blood is taken at acontrolled flow rate of at least 1 I/min, more particularly from 6 to 8I/min.

All the above-mentioned method variants can be combined with each otherin any way and order.

BRIEF DESCRIPTION OF THE INVENTION

The invention is described below, without restricting the generalconcept of the invention, by way of examples of embodiments withreference to the drawings, in which

FIG. 1 shows a block diagram of an illustration of the individualcomponents of an example of embodiment;

FIG. 2 shows a schematic view of the analysis unit;

FIG. 3 shows a schematic view of a reservoir and dosage unit; and

FIG. 4 a generalized block diagram of an example of embodiment.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

In FIG. 1, a block diagram illustrating all the components of anembodiment of a device in accordance with the invention is shown. Theuse of the device is explained in more detail using the example of ahuman patient P as an individual who has suffered a cardiac arrest.Applied to the patient P in the area of femoral vein in order take bloodare a blood withdrawal device BE shown as a catheter, from which a bloodflow path BL extends extracorporeally, which passes through varioustechnical components and from which at various points lines branch offand into which at various points lines open, which are discussed in moredetail below. Finally the blood flow path BL enters the patient again,more particularly in the area of the femoral artery to which a bloodreturns device BR shown as a catheter is also applied.

For controlled blood withdrawal from the patient P and for setting thereperfusion parameters under which the device to be described returns“modified blood” or reperfusate into the patient's blood circulation, aconveying unit F is provided along the blood flow path BL, which is moreparticularly in the form of a centrifugal pump and is to be seen as acomponent of the lightweight and portable CIRD. The conveying unit F canalso be variably adjusted in terms of conveying output, conveyingcharacteristics and duration, that is pressure, duration andpulsability, via an evaluation and control unit A/S yet to be describedin more detail. In addition, the portable CIRD has an oxygenator O, withwhich the blood taken from the patient is enriched with oxygen. Incertain cases, with the aid of the oxygenator, it is also possible todeplete oxygen from the patient's own blood. There is also a gas blenderG, which influences the blood CO₂ content, usually in the form ofdepletion of the CO₂ content in the patient's own blood. For individualtemperature control of the blood flow within the blood flow path BL, theoxygenator O is also connected to a heat exchanger unit. The heatexchanging characteristics are influenced in a controlled manner by theevaluation and control unit A/S. Finally, the portable CIRD unitcomprises a leukocyte filter through which the leukocyte content of thepatient's blood can be influenced.

A first by-pass line A1 is provided in the blood flow path BL directlyleaving the patient, via which some of the patient's blood is branchedoff into an analysis unit BA in which the patient's blood is analyzed bysensors with respect to various blood parameters.

In an expanded form of embodiment, the device of FIG. 1 may besupplemented with further functional units, which are able to modify ormanipulate the patient's blood in the following manner.

Units are thus provided for influencing the patient's blood throughextracorporeal pressure exertion on the patient in such a way that interms of time and space the pressure exertion takes place in apredeterminable manner on the patient evenly or selectively. Such unitsfor the mechanical influencing of the patient's blood can alternativelyalso be applied invasively and for intracorporeal pressure exertion onthe patient's blood.

In addition, units for the thermal influencing of the patient's bloodfor extracorporeal temperature control can be provided and designed sothat in terms of time and space, the temperature control takes place ina predeterminable manner on the patient evenly or selectively. Suchunits for the thermal influencing of the patient's blood canalternatively also be applied invasively and for intracorporealtemperature control of the patient's blood so that in terms of space andtime the temperature control takes place in a predeterminable mannerwithin the patient evenly or selectively.

Preferably, to return the blood to the body of the patient P, along theblood flow path, before or after the leukocyte filter LF at least onefurther, separate conveying device (not shown) can be provided, withwhich conveying characteristics can be set which are individual andabove all independent in relation to pulsability, flow pressure andspeed.

In FIG. 2, an analysis unit BA is shown schematically for more detailedexplanation. It is assumed that via line A1, part of the patient's bloodreaches the blood analyzing analysis unit BA. Within the analysis unitBA, more particularly in the form of a sensor unit, a number ofindividual sensors SE₁ to SE_(n) are provided, which analyze the bloodwith regard to various blood parameters. Advantageously brought togetherin the analysis/sensor unit are known sensors each one of which is ableto record at least one of the following non-exhaustively listedparameters: pH-value, partial oxygen pressure (pO₂), partial carbondioxide pressure (pCO₂), potassium content (K), sodium content (NA),calcium content (Ca), the base deviation designated as BE, also known asbase excess/base deficit with which metabolic disorders of the acid-basebalance can be detected, lactate value (La), glucose content (Gu) toname but a few.

Each individual sensor SE_(1 . . . n) determines one blood parameterSEE_(1 . . . n), characteristic of the patient's blood, which togetherproduce the so-called blood analysis result BAE which reflects thecurrent quality of the patient's own blood. More particularly, the bloodanalysis result is transmitted via a data transmission cable to theevaluation and control unit A/S in which the blood analysis result BAEundergoes separate analysis and evaluation based on medical evaluationcriteria.

The purpose of the device in accordance with the invention is ultimatelyto transform, through the addition of certain substances, the patient'sblood into a modified state which can be characterized in the fact thatthe specially “modified blood” or the reperfusate should not cause anytissue damage during initial reperfusion into the patient for thepurpose of the patient's resuscitation. In addition, it is intended toreduce/heal ischaemic damage which may have already occurred in certaintissue areas.

Within the evaluation and control unit A/S the current sensor-recordedindividual blood parameters SEE_(1 . . . n) of the patient's blood arecompared with blood parameter-specific references or nominal values,which are to be restored through modification of the patient's blood. Inaccordance with such an evaluation the type and quantity of the relevantsubstances to be added to the patient's blood are determined. Theevaluation/control unit is in informal communication with a reservoirunit R as well as a dosage unit D combined therewith, which are bothshown schematically in FIG. 3. In accordance with FIG. 3 the reservoirunit R comprises four individual reservoir chambers in which fourdifferent substances S₁, S₂, S₃ and S₄ are stored. More such reservoirchambers can of course be provided, that is in general reservoirchambers for storing n different substances. The individual reservoirsare each connected to a mixing container MB, whereby along theconnection lines dosage units in the form of stop valves V₁, V₂, V₃ andV₄ are provided. Depending on the current blood analysis result BAE andthe additive requirement determined by the evaluation/control unit forthe substance to be mixed to the patient's blood, the evaluation/controlunit generates control signals Si₁, Si₂, Si₃, Si₄ for operating thedosage units V₁ to V₄. Finally, the mixture of the individual substanceprepared in the mixing container MB is introduced into the blood flowpath BL.

In a variant, a monitoring unit M (see FIG. 1) is provided, which viasensors applied to the patient P, records physiological patientparameters, for example the mean arterial pressure, the central venouspressure, the pulmonary arterial pressure, oxygen saturation, as well asbody temperature, to name but a few. The physiological patent parametersare also transmitted by the monitoring unit M to the evaluation andcontrol unit A/S, where after being taken into consideration theevaluation and control unit generates the control signals Si_(1 . . . n)for the dosage unit.

Before the reperfusate is returned to the patient P via the blood flowpath BL, with the aid of the analysis unit BA, an analysis of the“modified blood”/reperfusate is carried out to ensure that a correctlycomposed/modified reperfusate is being returned to the patient. Forthis, a second by-pass line A2 is provided immediately upstream of theblood return device BR which diverts some of the “modifiedblood”/reperfusate into the analysis unit BA. In the analysis unit BA,repeat sensor recording of the individual blood parametersSEE_(1 . . . n) takes place, which undergoes a nominal/actual comparisonin the evaluation and control unit A/S. If deviations occur, thegenerated control signals Si₁, Si₂, Si₃, Si₄ are corrected in orderinfluence the dosage unit V₁ to V₄.

Furthermore, on the basis of the blood analysis results BAE and thephysiological patient parameters determined by the monitoring unit M,the evaluation and control unit generates control signals to control theconveying unit F determining the flow characteristics within the bloodflow path BL, as well as the heat exchanger WT determining thetemperature level of the reperfusate being infused into the patient,ultimately with the aim of tissue-protecting reperfusion of the“modified blood” back into the patient's blood circulation. In doing so,the parameters of the flow pressure, the flow rate, the pulsability,flow duration and temperature of the reperfusate are individuallymatched to the patient.

FIG. 4 shows a schematic blood diagram of a further embodiment of theinvention. Sensor unit SEH, provides information obtained from thebodily fluid, more particularly blood, of a patient P. The sensorsignals generated by the sensor unit SEH are forwarded to an analysisunit A which generates an analysis result representing the current stateof the bodily fluid/blood. Based on at least one evaluation criterion,for example, the analysis result is evaluated by an evaluation andcontrol unit A/S. The evaluation and control unit then generates controlor regulating signals for the controlled activation of an operative unitKE which influences the bodily fluid and, in particular, can be composedof at least one of the following sub-units: units which add at least onesubstance to the bodily fluid MS, units which mechanically influencebodily fluid MM and units which thermally influence bodily fluid. Eachof these units can be combined with joining units. Depending on theunits that can be activated by the evaluation and control unit A/S, thebodily fluid of the patient P undergoes therapeutic manipulation ormodification for the purpose of preventing ischaemic tissue damage.

The device in accordance with the invention is particularly compact and,if possible, in a single housing to assure as simple and fully automaticoperation as possible. The processes of taking the blood, bloodanalysis, addition of at least one substance to the patient's blood toobtain “modified blood,” and the reperfusion of the “modified blood”take place automatically and in situ, without further knowledge aboutthe person to be resuscitated having to be available. The device obtainsall information for successful reperfusion from the described sensordata sensors in the form of data from the automatic blood screening andsensor-detectable physiological data.

With the benefit of the device in accordance with the invention,controlled whole-body reperfusion can be carried out with which theduration of ischaemia, until irreversible damage to individual organs oreven the entire body, can be considerably increased compared with thecurrent narrow time limits.

LIST OF REFERENCES

-   BE Blood withdrawal device-   BR Blood return device-   BL Blood flow path-   BA Analysis unit-   R Reservoir unit-   D Dosage unit-   A1 Diversion line-   A2 By-pass line-   CIRD Basis module of the controlled integrated resuscitation device-   F Conveying unit-   O Oxygenator-   G Gas blender-   LF Leukocyte filter-   A/S Evaluation/control unit-   WT Heat exchanger-   M Monitoring unit-   S1, S2 . . . Substance-   Si₁ . . . Control signal-   V1, V2 . . . Dosage unit, valve-   MB Mixing container-   SE₁, SE₂ . . . Sensors-   SEE₁, SEE₂ . . . Sensor result-   BAE Blood analysis result-   A Analysis unit-   SEH Sensor unit-   KE Operative unit-   MS Unit for adding at least one substance to the bodily fluid-   MM Unit for mechanically influencing the bodily fluid-   MT Unit for thermally influencing the bodily fluid

The invention claimed is:
 1. In a system providing treatment of cardiacarrest by withdrawing blood from a patient's or an animal's circulatorysystem during the cardiac arrest and introducing at least modified bloodcontaining the withdrawn blood to which at least one substance has beenadded to provide whole body reperfusion of the circulatory system withthe modified blood during the treatment of cardiac arrest comprisingblood analysis means, for connection during the treatment of the cardiacarrest to the blood withdrawn from the circulatory system, fordetermining during the treatment of the cardiac arrest, a plurality ofparameters of the blood including at least pO2, pCO2, and pHrepresenting a current condition of the patient or animal duringtreatment of the cardiac arrest and an output representing thedetermination during the treatment of the cardiac arrest, storage meansfor storing during the treatment of the cardiac arrest at least twosubstances from which the at least one substance is selected for thetreatment of the cardiac arrest, means for selecting during thetreatment of the cardiac arrest, based on the analysis, a type andquantity of the at least one substance from the storage means which isadded to the withdrawn blood to form the modified blood, which uponintroduction into the circulatory system during the treatment of thecardiac arrest lessens or prevents ischemic tissue damage and means forintroducing during the treatment of the cardiac arrest at least themodified blood into the circulatory system which provides the whole bodyreperfusion of the circulatory system during the treatment of thecardiac arrest which lessens or prevents the ischemic tissue damageduring the treatment of the cardiac arrest, the method comprising:withdrawing the blood from the circulatory system during the cardiacarrest; analyzing the blood withdrawn from the circulatory system withthe blood analysis means during the cardiac arrest and determiningduring the treatment of the cardiac arrest the plurality of parametersof the blood including at least pO₂, pCO₂, and the pH; selecting, basedon the determination of at least the pO2, the pCO2 and the pH, duringthe treatment of the cardiac arrest, a type and quantity of the at leastone substance from the stored substances which is added to the blood toform the modified blood which upon introduction of the modified bloodinto the circulatory system during the treatment of the cardiac arrestlessens or prevents ischemic tissue damage; and introducing at least themodified blood into the circulatory system during the treatment of thecardiac arrest which provides the whole body reperfusion of thecirculatory system with the modified blood to treat the cardiac arrestwhich lessens or prevents ischemic tissue damage during the treatment ofthe cardiac arrest.
 2. A method in accordance with claim 1, comprising:pumping a regulated flow of the modified blood into the circulatorysystem during the treatment of the cardiac arrest.
 3. A method inaccordance with claim 1, comprising: monitoring at least onephysiological parameter of the patient or animal during the cardiacarrest and providing a representation of the at least one physiologicalparameter during the cardiac arrest; and wherein: selecting a type andquantity of the at least one substance to form the modified blood isalso based on the representation.
 4. A method in accordance with claim2, comprising: monitoring at least one physiological parameter of thepatient or animal during the cardiac arrest and providing arepresentation of the at least one physiological parameter during thecardiac arrest; and wherein: selecting a type and quantity of the atleast one substance to form the modified blood is also based on therepresentation.
 5. A method of treating cardiac arrest, by withdrawingblood from the patient's or animal's circulatory system during thetreatment of the cardiac arrest and introducing at least modified bloodcontaining the blood to which at least one substance has been addedduring the treatment of the cardiac arrest to provide whole bodyreperfusion of the circulatory system with the modified blood during thetreatment of the cardiac arrest comprising: withdrawing the blood fromthe circulatory system during the treatment of the cardiac arrest;analyzing the blood withdrawn from the circulatory system during thetreatment of the cardiac arrest to determine a plurality of parametersof the blood including at least the pO₂, pCO₂, and pH representing acurrent condition of the patient or animal during the cardiac arrest;storing at least two substances from which at least one substance isselected; selecting, based on the determination of at least the pO2, thepCO2 and the pH, during the treatment of the cardiac arrest a type andquantity of at least one of the at least two stored substances which isadded to the withdrawn blood to form the modified blood, which uponintroduction into the circulatory system during the treatment of thecardiac arrest, lessens or prevents ischemic tissue damage during thetreatment of the cardiac arrest; and introducing the modified blood intothe circulatory system during the treatment of the cardiac arrest whichprovides the whole body reperfusion of the circulatory system with themodified blood which lessens or prevents the ischemic tissue damageduring the treatment of the cardiac arrest.
 6. A method in accordancewith claim 5, comprising: pumping the modified blood into thecirculatory system.
 7. A method in accordance with claim 5, comprising:monitoring at least one physiological parameter of the patient or animalduring the cardiac arrest and providing a representation of the at leastone physiological parameter during the treatment of cardiac arrest; andwherein: the selection of the at least one substance to form themodified blood is also based on the representation.
 8. A method inaccordance with claim 6, comprising: monitoring at least onephysiological parameter of the patient or animal during the cardiacarrest and providing output representation of the at least onephysiological parameter during the treatment of cardiac arrest; andwherein: the selection of the at least one substance to form themodified blood is also based on the representation.
 9. A method inaccordance with claim 5, comprising: mixing at least one storedsubstance with the withdrawn blood to form the modified blood during thetreatment of cardiac arrest.
 10. A method in accordance with claim 6,comprising: mixing at least one stored substance with the withdrawnblood to form the modified blood during the treatment of cardiac arrest.11. A method in accordance with claim 7, comprising: mixing at least onestored substance with the withdrawn blood to form the modified bloodduring the treatment of cardiac arrest.
 12. A method in accordance withclaim 8, comprising: mixing at least one stored substance with thewithdrawn blood to form the modified blood during the treatment ofcardiac arrest.
 13. A method in accordance with claim 5, comprising:storing a plurality of substances in solid, liquid or gaseous form, fromwhich the at least one substance is selected by the type and quantity tobe mixed with the blood to form the modified blood during the treatmentof cardiac arrest.
 14. A method in accordance with claim 6, comprising:storing a plurality of substances in solid, liquid or gaseous form, fromwhich the at least one substance is selected by the type and quantity tobe mixed with the blood to form the modified blood during the treatmentof cardiac arrest.
 15. A method in accordance with claim 7, comprising:storing a plurality of substances in solid, liquid or gaseous form, fromwhich the at least one substance is selected by the type and quantity tobe mixed with the blood to form the modified blood during the treatmentof cardiac arrest.
 16. A method in accordance with claim 8, comprising:storing a plurality of substances in solid, liquid or gaseous form, fromwhich the at least one substance is selected by the type and quantity tobe mixed with the blood to form the modified blood during the treatmentof cardiac arrest.
 17. A method in accordance with claim 9, comprising:storing a plurality of substances in solid, liquid or gaseous form, fromwhich the at least one substance is selected by the type and quantity tobe mixed with the blood to form the modified blood during the treatmentof cardiac arrest.
 18. A method in accordance with claim 10, comprising:storing a plurality of substances in solid, liquid or gaseous form, fromwhich the at least one substance is selected by the type and quantity tobe mixed with the blood to form the modified blood during the treatmentof cardiac arrest.
 19. A method in accordance with claim 11, comprising:storing a plurality of substances in solid, liquid or gaseous form, fromwhich the at least one substance is selected by the type and quantity tobe mixed with the blood to form the modified blood during the treatmentof cardiac arrest.
 20. A method in accordance with claim 12, comprising:storing a plurality of substances in solid, liquid or gaseous form, fromwhich the at least one substance is selected by the type and quantity tobe mixed with the blood to form the modified blood during the treatmentof cardiac arrest.
 21. A method in accordance with claim 5, comprising:selecting during the treatment of cardiac arrest the at least onesubstance from at least one of an alkaline buffer solution, an acidicbuffer solution, substances affecting sodium, potassium and/or calciumcontent, blood-thinning substances, free radical trapping agents,glutamate, aspartame, heart-rhythm-stabilizing substances, substancesinfluencing leukocyte count and osmotically-active substances includingsalts, glucoses and proteins.
 22. A method in accordance with claim 6,comprising: selecting during the treatment of cardiac arrest the atleast one substance from at least one of an alkaline buffer solution, anacidic buffer solution, substances affecting sodium, potassium and/orcalcium content, blood-thinning substances, free radical trappingagents, glutamate, aspartame, heart-rhythm-stabilizing substances,substances influencing leukocyte count and osmotically-active substancesincluding salts, glucoses and proteins.
 23. A method in accordance withclaim 7, comprising: selecting during the treatment of cardiac arrestthe at least one substance from at least one of an alkaline buffersolution, an acidic buffer solution, substances affecting sodium,potassium and/or calcium content, blood-thinning substances, freeradical trapping agents, glutamate, aspartame, heart-rhythm-stabilizingsubstances, substances influencing leukocyte count andosmotically-active substances including salts, glucoses and proteins.24. A method in accordance with claim 8, comprising: selecting duringthe treatment of cardiac arrest the at least one substance from at leastone of an alkaline buffer solution, an acidic buffer solution,substances affecting sodium, potassium and/or calcium content,blood-thinning substances, free radical trapping agents, glutamate,aspartame, heart-rhythm-stabilizing substances, substances influencingleukocyte count and osmotically-active substances including salts,glucoses and proteins.
 25. A method in accordance with claim 9,comprising: selecting during the treatment of cardiac arrest the atleast one substance from at least one of an alkaline buffer solution, anacidic buffer solution, substances affecting sodium, potassium and/orcalcium content, blood-thinning substances, free radical trappingagents, glutamate, aspartame, heart-rhythm-stabilizing substances,substances influencing leukocyte count and osmotically-active substancesincluding salts, glucoses and proteins.
 26. A method in accordance withclaim 10, comprising: selecting during the treatment of cardiac arrestthe at least one substance from at least one of an alkaline buffersolution, an acidic buffer solution, substances affecting sodium,potassium and/or calcium content, blood-thinning substances, freeradical trapping agents, glutamate, aspartame, heart-rhythm-stabilizingsubstances, substances influencing leukocyte count andosmotically-active substances including salts, glucoses and proteins.27. A method in accordance with claim 11, comprising: selecting duringthe treatment of cardiac arrest the at least one substance from at leastone of an alkaline buffer solution, an acidic buffer solution,substances affecting sodium, potassium and/or calcium content,blood-thinning substances, free radical trapping agents, glutamate,aspartame, heart-rhythm-stabilizing substances, substances influencingleukocyte count and osmotically-active substances including salts,glucoses and proteins.
 28. A method in accordance with claim 12,comprising: selecting during the treatment of cardiac arrest the atleast one substance from at least one of an alkaline buffer solution, anacidic buffer solution, substances affecting sodium, potassium and/orcalcium content, blood-thinning substances, free radical trappingagents, glutamate, aspartame, heart-rhythm-stabilizing substances,substances influencing leukocyte count and osmotically-active substancesincluding salts, glucoses and proteins.
 29. A method in accordance withclaim 7, wherein: monitoring the at least one physiological parameterduring the treatment of cardiac arrest comprises monitoring at least oneof mean arterial pressure, central nervous pressure, pulmonary arterypressure, oxygen saturation and blood temperature.
 30. A method inaccordance with claim 8, wherein: monitoring the at least onephysiological parameter during the treatment of cardiac arrest comprisesmonitoring at least one of mean arterial pressure, central nervouspressure, pulmonary artery pressure, oxygen saturation and bloodtemperature.
 31. A method in accordance with claim 7, wherein: the atleast one physiological parameter which is monitored during thetreatment of cardiac arrest comprises at least one of mean arterialpressure, central nervous pressure, pulmonary artery pressure, oxygensaturation and blood temperature and the method further comprises:generating a representation of at least one of the arterial pressure,the central nervous pressure, the pulmonary artery pressure, the oxygensaturation and the blood temperature; and wherein the selection of thetype and quantity of the at least one substance from storage for formingthe modified blood is also based on the representation.
 32. A method inaccordance with claim 8, wherein: the at least one physiologicalparameter which is monitored during the treatment of cardiac arrestcomprises at least one of mean arterial pressure, central nervouspressure, pulmonary artery pressure, oxygen saturation and bloodtemperature and the method further comprises: generating arepresentation of at least one of the arterial pressure, the centralnervous pressure, the pulmonary artery pressure, the oxygen saturationand the blood temperature; and wherein the selection of the type andquantity of the at least one substance from storage for forming themodified blood is also based on the representation.
 33. A method inaccordance with claim 5, wherein: the plurality of parameters of theblood further includes potassium content, calcium content, base excess,lactate value or glucose content.
 34. A method in accordance with claim6, wherein: the plurality of parameters of the blood further includespotassium content, calcium content, base excess, lactate value orglucose content.
 35. A method in accordance with claim 5, comprising:providing during the treatment of cardiac arrest a heat exchanger in ablood flow path, disposed between a point of withdrawal of the bloodfrom the circulatory system and point of return of at least the modifiedblood into the circulatory system which, based on the analysis, controlsa temperature of at least the modified blood introduced into thecirculatory system to perform whole body reperfusion of the circulatorysystem.
 36. A method in accordance with claim 7, comprising: providingduring the treatment of cardiac arrest a heat exchanger in a blood flowpath, disposed between a point of withdrawal of the blood from thecirculatory system and point of return of at least the modified bloodinto the circulatory system which, based on the analysis, controls atemperature of at least the modified blood introduced into thecirculatory system to perform whole body reperfusion of the circulatorysystem.
 37. A method in accordance with claim 5, comprising:controlling, based on the analysis, at least one of pressure, flow rateand temperature of at least the modified blood introduced into thecirculatory system to perform whole body reperfusion of the circulatorysystem.
 38. A method in accordance with claim 7, comprising:controlling, based on the analysis, at least one of pressure, flow rateand temperature of at least the modified blood introduced into thecirculatory system to perform whole body reperfusion of the circulatorysystem.
 39. A method in accordance with claim 5, comprising: providingduring the cardiac arrest an oxygen enrichment and depletion means in ablood flow path, disposed between a point of withdrawal of the bloodfrom the circulatory system and a point of return of at least themodified blood into the circulatory system for analyzing an amount ofoxygen in the withdrawn blood and controlling with the oxygen and thedepletion means, based on an analysis of oxygen in the withdrawn blood,oxygen present in at least the modified blood which is introduced intothe circulatory system to provide whole body reperfusion of thecirculatory system.
 40. A method in accordance with claim 7, comprising:providing during the cardiac arrest an oxygen enrichment and depletionmeans in a blood flow path disposed between a point of withdrawal fromthe circulatory system and a point of return of at least the modifiedinto the circulatory system for analyzing an amount of oxygen in thewithdrawn blood and controlling with the oxygen and the depletion means,based on an analysis of oxygen in the withdrawn blood, oxygen present inat least the modified blood which is introduced into the circulatorysystem to provide whole body reperfusion of the circulatory system. 41.A method providing treatment of cardiac arrest, circulatory arrest orstroke by withdrawal of blood from a patient's or an animal'scirculatory system during the cardiac arrest, circulatory arrest orstroke and introducing at least modified blood containing the blood towhich at least one substance has been added to provide whole bodyreperfusion of the circulatory system with the modified blood during thetreatment of the cardiac arrest, circulatory arrest or strokecomprising: withdrawing the blood from the circulatory system during thetreatment of the cardiac arrest, circulatory arrest or stroke; analyzingthe blood withdrawn from the circulatory system during the treatment ofthe cardiac arrest, circulatory arrest or stroke to determine aplurality of parameters of the blood including at least pO2, pCO2, andpH representing a current condition of the patient or animal during thetreatment of cardiac arrest, circulatory arrest or stroke; storing atleast two substances from which at least one substance is selected toform the modified blood during the treatment of the cardiac arrest,circulatory arrest or stroke; selecting, based on the determination ofat least the pO2, the pCO2 and the pH, during the treatment of cardiacarrest, circulatory arrest or stroke, a type and quantity of at leastone of the at least two stored substances which is added to thewithdrawn blood to form the modified blood, which upon introduction intothe circulatory system to provide whole body reperfusion of thecirculatory system during the treatment of the cardiac arrest,circulatory arrest or stroke, lessens or prevents ischemic tissue damageduring the treatment of the cardiac arrest, circulatory arrest orstroke; and introducing the modified blood into the circulatory systemto provides whole body reperfusion of the circulatory system during thetreatment of the cardiac arrest, circulatory arrest or stroke, whichlessens or prevents the ischemic tissue damage during the treatment ofcardiac arrest, circulatory arrest or stroke.
 42. A method in accordancewith claim 41 comprising: prior to addition of the modified blood, atleast one substance is added to the circulatory system.